Abstract

Research in the area of psychoneuroimmunology has suggested the possibility of self regulated immune system improvement. Psychological treatments involving relaxation have been found to increase levels of salivary immunoglobulin A (sIgA). High levels of sIgA have been found to protect against cold and flu infections.

Research in the area of exercise immunology has found that chronic over­exercising suppresses the immune system and increases the incidence of colds and flu. However, preliminary research suggests that a moderate amount of aerobic exercise may enhance the immune system. Only two previous studies have explored the effects of moderate aerobic exercise on sIgA. Tharp (1991) found an increase in levels of sIgA in boys after a basketball game. McDowell et al. (1991) found no increase of sIgA levels in young adult males after a treadmill exercise.

No previous study has investigated the clinical efficacy of moderate aerobic exercise on upper respiratory tract infection (URTI). Neither has any study explored the effects of mild aerobic exercise on levels of slgA or incidence of URTI. Furthermore no previous study has explored the clinical efficacy of the psychological techniques employed in this study for adults.

The first study of the present research investigated the effect of mild and moderate aerobic exercise and relaxation on levels of sIgA in both active and sedentary subjects. Absolute concentration of sIgA increased for both active and sedentary groups in all three conditions (mild aerobic exercise, moderate aerobic exercise and relaxation).

The second study of the present research explored the longer term effects of stress reduction and moderate aerobic exercise on levels of sIgA, levels of stress and incidence of URTI in a group of undergraduate university students as they approached end of semester exams. Approximately half the students exercised regularly, and the other half remained sedentary throughout the study. The Treatment Group comprised of both active and sedentary students, as did the control group.

The results of this study found that incidence of upper respiratory tract infection (URTI) decreased in the Treatment group but not in the Control group, irrespective of exercise. The difference in days with URTI was significant eight weeks after treatment. Levels of sIgA significantly increased from before to after relaxation, but the increase did not extend to the sIgA sample time point one week later. Therefore background levels of sIgA did not increase in the Treatment Group compared to the Control Group over the course of treatment. Stress profiles as measured by the Profile of Mood States (POMS) and a quality of life questionnaire, the SF-36 indicated that negative affect did not differ between the groups. However, positive affect in the form of perceived General Health was higher in the Treatment Group compared with the Control Group. Subjects in the treatment group who exercised regularly had higher Vigor than the other three groups. General Health and Vitality was also higher for exercisers than non exercisers.

The studies in this research clearly demonstrate that psychological treatment is associated with a decrease in days of cold and flu. Although levels of sIgA increased during relaxation and aerobic exercise in the short term, there was no long term increase over the course of treatment either in regular exercisers or in sedentary subjects. A short term increase in sIgA may have been sufficient to decrease the number of days ill. The psychologically induced increase in sIgA may be one mechanism responsible for the decrease in ill days in university students approaching exams.